Psychological Effects of Military Service in Vietnam: A Meta-analysis

To integrate research on the psychological status of Vietnam veterans, we conducted a meta-analysis of 67 studies appearing in the literature from 1972 through 1985. Mean effect size, representing the comparison between Vietnam veterans and others on a variety of mental health indicators, was a significant –0.53. There was a tendency for larger effect sizes in studies that appeared later, were published by researchers affiliated with the Veterans Administration, documented combat history, but did not incorporate a comparison group. Vietnam veterans were significantly different from both Vietnam-era veterans and nonveterans, with the pattern of differences indicating a "Vietnam effect."